Enhancing the Energy Content of Melawan Coal through H2SO4 and NaOH Demineralization

Aliyu Buba Ngulde(1*), Wan Azlina Wan Ab Karim Ghani(2), Nazmi Mat Nawi(3), Umer Rashid(4), Kiman Silas(5)
(1) Institute of Plantation Studies, Universiti Putra Malaysia (UPM), Serdang, Selangor 43400, Malaysia; Department of Chemical Engineering, Faculty of Engineering, University of Maiduguri, PMB 1069, Maiduguri, Borno State, Nigeria
(2) Sustainable Process Engineering Research Center (SPERC), Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
(3) Institute of Plantation Studies, Universiti Putra Malaysia (UPM), Serdang, Selangor 43400, Malaysia; Department of Biological and Agricultural Engineering, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
(4) Institute of Nanoscience and Nanotechnology (ION2), Universiti Putra Malaysia, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia; Center of Excellence in Catalysis for Bioenergy and Renewable Chemicals (CBRC), Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand; Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand
(5) Department of Chemical Engineering, Faculty of Engineering, University of Maiduguri, PMB 1069, Maiduguri, Borno State, Nigeria
(*) Corresponding Author
Abstract
The objective of this study was to compare the calorific values, proximate analysis, ultimate analysis, SEM-EDX, XRF, FTIR spectroscopy, and TGA of the control feedstock and coal samples treated with different acid-alkali formulations. We also evaluated the effectiveness of the acid and alkali treatments, individually and in combination, on the structural and chemical properties of Melawan coal. The TGA results indicated that all treated coal samples showed reduced weight loss compared to raw coal, indicating the removal of minerals and volatile components owing to the treatment processes. Based on the DTG curve, the combination treatment (acid followed by base) somewhat stabilizes the coal, leading to a broader and less intense peak. EDS analysis revealed that both H2SO4 and NaOH treatments, individually and in combination, significantly altered the elemental composition of the coal. According to FTIR analysis, the presence of carbonyl groups can affect the performance of coal in processes such as gasification, pyrolysis, or combustion, making it a key functional group of interest for evaluating post-treatment coal properties. The removal of mineral impurities can lead to a higher calorific value, making coal more suitable for energy generation applications.
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